In order to complete the behavioral and physiological assessment of rhesus monkeys receiving parietal cortex lesions either as infants (3-7 weeks) or as juveniles (18-24 weeks), continuation funds are requested. Infants given either partial (Brodmann's areas 3 or 1 and 2) or total (areas 3, 1, and 2) or total (areas 1,3, and 2) lesions of the hand representations in the primary somatic sensory cortex (SI) show complete recovery of discrimination capacity following surgery. Those infants receiving total lesions are performing at normal levels immediately following surgery while those receiving partial lesions may require as long as 16 weeks to obtain normal performance. By contrast, the juvenile group is demonstrating a degree of impairment on these same tasks comparable to that found in the adult-lesioned animals in a previous study. Both the infant- and juvenile-lesioned groups will be retested on size and texture threshold tasks at 18-24 months postsurgically to determine the stability of the impairment of recovery described in the initial postsurgical testing. As a check of the adequacy of the lesions, electrophysiological and histological studies of the lesioned hemispheres will be done in the cortex adjacent to the lesions, to determine the somatic sensory input to the spared cortex. Microscopic examination of stained sections of the lesioned hemisphere will be used to define the limits of the lesions relative to the cytoarchitecture of remaining cortical areas.